Critical evaluation of non-thermal plasma as an innovative accelerated lipid oxidation technique in fish oil

Shade of Innovative Food Processing Techniques: Potential Inducing Factors of Lipid Oxidation

With increasing environmental awareness and consumer demand for high-quality food products, industries are strongly required for technical innovations. The use of various emerging techniques in food processing indeed brings many economic and environmental benefits compared to conventional processes. However, lipid oxidation induced by some "innovative" processes is often "an inconvenient truth", which is scarcely mentioned in most studies but should not be ignored for the further improvement and optimization of existing processes. Lipid oxidation poses a risk to consumer health, as a result of the possible ingestion of secondary oxidation products. From this point of view, this review summarizes the advance of lipid oxidation mechanism studies and mainly discloses the shade of innovative food processing concerning lipid degradation. Sections involving a revisit of classic three-stage chain reaction, the advances of polar paradox and cut-off theories, and potential lipid oxidation factors from emerging techniques are described, which might help in developing more robust guidelines to ensure a good practice of these innovative food processing techniques in future.

Effects of Bacterioruberin-Rich Haloarchaeal Carotenoid Extract on the Thermal and Oxidative Stabilities of Fish Oil

This study aimed to assess the efficacy of a bacterioruberin-rich carotenoid extract (HAE) derived from the halophilic archaea Halorubrum ezzemoulense DSM 19316 in protecting crude fish oil against thermal oxidation. The research used fish oil derived from anchovies, which had a peroxide value (PV) of 6.44 ± 0.81 meq O2 kg-1. To assess the impact of HAE on the thermal stability and post-oxidation characteristics of fish oil, several concentrations of HAE were added to the fish oil samples: 0 ppm (no additive) (HAE0), 50 ppm (HAE50), 100 ppm (HAE100), 500 ppm (HAE500), and 1000 ppm (HAE1000). Furthermore, a control group was established with the addition of 100 ppm butylated hydroxytoluene (BHT100) in order to evaluate the effectiveness of HAE with a synthetic antioxidant that is commercially available. Prior to the fast oxidation experiment, thermogravimetric analysis was conducted on samples from all experimental groups. At the conclusion of the examination, it was seen that the HAE500 and HAE1000 groups exhibited a delay in the degradation temperature. The experimental groups underwent oxidation at a temperature of 55.0 ± 0.5 °C for a duration of 96 h. The measurement of PV was conducted every 24 h during this time. PV in all experimental groups exhibited a time-dependent rise (p < 0.05). However, the HAE500 group had the lowest PV measurement at the conclusion of the 96 h period (p < 0.05). Significant disparities were detected in the fatty acid compositions of the experimental groups at the completion of the oxidation experiment. The HAE500 group exhibited the highest levels of EPA, DHA, and ΣPUFA at the end of oxidation, with statistical significance (p < 0.05). Through the examination of volatile component analysis, specifically an oxidation marker, it was shown that the HAE500 group exhibited the lowest level of volatile components (p < 0.05). Consequently, it was concluded that the addition of HAE to fish oil provided superior protection compared to BHT at an equivalent rate. Moreover, the group that used 500 ppm HAE demonstrated the highest level of performance in the investigation.

A comprehensive review on impact of non-thermal processing on the structural changes of food components

Non-thermal food processing is a viable alternative to traditional thermal processing to meet customer needs for high-quality, convenient and minimally processed foods. They are designed to eliminate elevated temperatures during processing and avoid the adverse effects of heat on food products. Numerous thermal and novel non-thermal technologies influence food structure at the micro and macroscopic levels. They affect several properties such as rheology, flavour, process stability, texture, and appearance at microscopic and macroscopic levels. This review presents existing knowledge and advances on the impact of non-thermal technologies, for instance, cold plasma treatment, irradiation, high-pressure processing, ultrasonication, pulsed light technology, high voltage electric field and pulsed electric field treatment on the structural changes of food components. An extensive review of the literature indicates that different non-thermal processing technologies can affect the food components, which significantly affects the structure of food. Applications of novel non-thermal technologies have shown considerable impact on food structure by altering protein structures via free radicals or larger or smaller molecules. Lipid oxidation is another process responsible for undesirable effects in food when treated with non-thermal techniques. Non-thermal technologies may also affect starch properties, reduce molecular weight, and change the starch granule's surface. Such modification of food structure could create novel food textures, enhance sensory properties, improve digestibility, improve water-binding ability and improve mediation of gelation processes. However, it is challenging to determine these technologies' influence on food components due to differences in their primary operation and equipment design mechanisms and different operating conditions. Hence, to get the most value from non-thermal technologies, more in-depth research about their effect on various food components is required.

Advanced techniques in edible oil authentication: A systematic review and critical analysis

Adulteration of edible substances is a potent contemporary food safety issue. Perhaps the overt concern derives from the fact that adulterants pose serious ill effects on human health. Edible oils are one of the most adulterated food products. Perpetrators are adopting ways and means that effectively masks the presence of the adulterants from human organoleptic limits and traditional oil adulteration detection techniques. This review embodies a detailed account of chemical, biosensors, chromatography, spectroscopy, differential scanning calorimetry, non-thermal plasma, dielectric spectroscopy research carried out in the area of falsification assessment of edible oils for the past three decades and a collection of patented oil adulteration detection techniques. The detection techniques reviewed have some advantages and certain limitations, chemical tests are simple; biosensors and nuclear magnetic resonance are rapid but have a low sensitivity; chromatography and spectroscopy are highly accurate with a deterring price tag; dielectric spectroscopy is rapid can be portable and has on-line compatibility; however, the results are susceptible to variation of electric current frequency and intrinsic factors (moisture, temperature, structural composition). This review paper can be useful for scientists or for knowledge seekers eager to be abreast with edible oil adulteration detection techniques.

Role of antioxidants on physicochemical properties and in vitro bioaccessibility of β-carotene loaded nanoemulsion under thermal and cold plasma discharge accelerated tests

The effects of water soluble antioxidant (ascorbic acid and EDTA), fat soluble antioxidant (α-tocopherol) and amphiphilic antioxidant (ascorbyl palmitate; AP) on the chemical physics and bioaccessibility of β-carotene loaded nanoemulsions (CNE) were investigated. During accelerated storage at 45 °C for 15 days, AP showed the highest protective actions against particle size growth, color fading, lipid oxidation, and β-carotene degradation in CNE (p < 0.05). CNE with AP was then subjected to treat with cold plasma (CP) induced reactive species system under various powers and contact times compared to control. AP was able to protect physical and oxidative stabilities of CNE as well as β-carotene integrity. The highest in vitro lipid digestibility, bioaccessibility and β-carotene stability were found in CNE with AP (p < 0.05). However, those properties were lowered after CP exposure. The results indicated that AP was a promising antioxidant in improving physical stability, oxidative stability, β-carotene retention, and β-carotene bioaccessibility of CNE.

Identification of Key Off-Flavor Compounds in Thermally Treated Watermelon Juice via Gas Chromatography-Olfactometry-Mass Spectrometry, Aroma Recombination, and Omission Experiments

Thermally treated watermelon juice (TW) presents a strong unpleasant smell, resulting in poor consumer acceptance. It is necessary to identify the key off-flavor compounds in TW. Solid-phase microextraction (SPME) and solvent-assisted flavor evaporation (SAFE) coupled with gas chromatography–olfactometry–mass spectrometry (GC–O–MS) were applied to the extraction and analysis of the volatile compounds in TW. Five aroma-active compounds and seven off-flavor compounds were quantitatively analyzed by the standard curve method. Based on the flavor dilution factor (FD), odor attribute, odor activity value (OAV) of volatile compounds, and partial least-squares regression (PLSR) analysis, seven key off-flavor compounds were preliminarily identified as follows: (E)-2-heptenal, decanal, octanol, diisopropyl disulfide, hexanol, (E)-2-decenal, and (E)-2-octenol. Aroma recombination proved that these off-flavor compounds above had a negative impact on the overall flavor in TW. Omission experiments were taken to confirm them further. Finally, octanol, diisopropyl disulfide, and (E)-2-decenal were identified as the most potent off-flavor compounds in TW.

Effects of plasma treatment on the oxidative stability of vegetable oil containing antioxidants

Plasma, the fourth stage of matter, is a partially or wholly ionized state of gas. Degree of lipid oxidation and effects of antioxidants were evaluated in bulk oils at plasma treatment. Significant changes in the conjugated dienoic acid were induced after 10 min of plasma treatment, which corresponded to treatment for 2.5 h at 100 °C and 48 h at 60 °C. Tocopherol stability in the stripped corn oil was significantly higher than that in medium-chain triacylglycerol after the plasma treatment. The antioxidant capacities of 10 μM of α-tocopherol and sesamol were higher than that of β-carotene, and synergistic effects among α-tocopherol, sesamol, and β-carotene were not observed. Added α-tocopherol and sesamol decreased CDA formation by 33 and 30% compared to control samples after plasma treatment. Moisture content in oils decreased significantly about 20% moisture after 6 min plasma treatment. Lipid oxidation could be an important issue in plasma-treated lipid-rich products.

Recent advancements in the application of non-thermal plasma technology for the seafood industry

Non-thermal plasma (NTP) is one of the most promising minimal processing methods for the food industry. However up until recently there are limited studies which would report the application and effect of NTP on processed seafood. The objective of this review is to highlight the recent findings and advancements in the application of NTP within the fish and other seafood industry, including direct application of fresh and dried fish and seafood with as well as indirect application of plasma activated water and seafood industry wastewater purification. The article also summarizes the effect of plasma treatment on microbiological quality, physicochemical and sensory properties and oxidation rate of treated fish and seafood. NTP has high potential to be used within various fields of seafood industry. It is especially effective in treatment of dried seafood products, but the use of plasma activated water during various processing steps such as seafood washing could be also beneficial. Moreover NTP could also be used as a cost effective and environmentally friendly method for seafood wastewater purification.

Chemical Modifications of Lipids and Proteins by Nonthermal Food Processing Technologies

A range of nonthermal techniques have demonstrated process efficacy in ensuring product safety, extension of shelf life, and in general a retention of key quality attributes. However, various physical, chemical and biochemical effects of nonthermal techniques on macro and micro nutrients are evident, leading to both desirable and undesirable changes in food products. The objective of this review is to outline the effects of nonthermal techniques on food chemistry and the associated degradation mechanisms with the treatment of foods. Oxidation is one of the key mechanisms responsible for undesirable effects induced by nonthermal techniques. Degradation of key macromolecules largely depends on the processing conditions employed. Various extrinsic and intrinsic control parameters of high-pressure processing, pulsed electric field, ultrasound processing, and cold atmospheric plasma on chemistry of processed food are outlined. Proposed mechanisms and associated degradation of macromolecules, i.e., proteins, lipids, and bioactive molecules resulting in food quality changes are also discussed.